392 E. Verstraelen et al. Table 35.1 Wind-off characteristics of the NLPF Characteristic Symbol Value Unit Dimensions of the wing Span s 800 [mm] Distance (flap axis wing root) s1 65 [mm] Distance (flap axis wing tip) s2 865 [mm] Chord c 200 [mm] Half chord b 100 [mm] Thickness t 4 [mm] Position of the center of mass xcg 1=2c [mm] Flap properties Linear stiffness K 5 [Nm/rad] Inertia I 0:42 [kgm2] Damping 1 [%] Frequency f 0:85 [Hz] Pitch properties Inertia I 0:029 [kgm2] Flexural axis position xf 0:3c [mm] Relative position of xf and xcg a xf xcg b [–] Linear stiffness coefficient K 10:1 [Nm/rad] Quadratic stiffness coefficient K ;2 0 [Nm/rad2] Cubic stiffness coefficient K ;3 858 [Nm/rad3] Damping 0:3 [%] Frequency f 3:1 [Hz] Position of the sensors Distance between A1 and A2 sacc 200 [mm] Distance between A2 and A3 cacc 180 [mm] Distance between D1 and D2 slas 205:5 [mm] Distance between D2 and D3 cacc 168:5 [mm] Fig. 35.4 Mode shapes of NLPFW I S S I R R C c c c c P P C k k k k C M ;NL. / M ;NL. / D M”; ext.t/ M™; ext.t/ (35.3) M ;NL D0 M ;NL Dknl;3 3 (35.4) where the inertia stiffness and damping parameters are given in Table 35.1. A nonlinear torque is applied only to the pitch DOF and it is a cubic function of . The flap and pitch aerodynamic moments, M and M respectively, are computed using strip theory (see for instance Bisplinghoff et al. [11]), which calculates the total 3D aerodynamic loads as sums of 2D loads, dLanddM , acting on small
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